Improvement Of The Insect-resistance Of Rice Restorer Line Zhenhui084 And Yihui9

Rice, as one of the staple food crops in China, is severely confined at its growth period by stem borer. One of the breeding targets of green super rice is to breed the variety that can resist lepidopteran insects, achieving less input, high output and protect environments. In the past decade, many kind of Bt genes have been introgressed into rice and expressed effectively and stablly in our university, and the resistance againt lepidopteran insects also reached over 98%. T1C-19 is one of the best transgenic materials introgressed with cry1C*, which has been applied to the productive experiment.The objective of this study was to improve the lepidopteran insect resistance of Zhenhui084 and Yihui9 by MAS and backcrossing methods. Cry1C* was used as target gene for the lepidopteran insect resistance. Then, the new indica rice restorer lines containing cry1C* were crossed with several rice sterile lines for selecting superior heterosis combinations. The main results are as follows:1. The Bt gene cy1C* was introgressed into recurrent parent Zhenhui084 and Yihui9. Eight breeding lines have been developed by using MAS. The agronomic traits of four breeding lines with genetic background of Zhenhui084 were stable and similar to Zhenhui084, and another four breeding lines with genetic background of Yihui9 were similar to Yihui9.2. Two recipient parents, eight new breeding lines and twelve sterile lines were chosen to analyze the combining ability in grain yield and main agronomic traits the way of pxq incomplete diallele cross (NCâ…¡) design in 2009 and 2010. The results showed that the main agronomic traits of improved lines were similar to Zhenhui084 and Yihui9. JY8185-1 and JY8202-1 had a higher general combining ability (GCA) effect for yield per plant; 1000-grain weight was the highest GCA effect for JY8181-2; plant height and panicle length of GCA effect were the highest for JY8201-2 whoes variance of effcet of specific combining ability was maximum in panicle length.3. Investigating under the field conditions without pesticide-applying showed that eight new breeding restorer lines carrying cry1C* gene and their F1 hybrids showed high resistance against insect.4. The result of Bt protein assessment at heading stages showed that Bt proteins of eight new breeding restorer lines were expressed, which illustrated that cry1C* genes in these new restorer lines and also proved the accuracy of the investigation result of field stem borer resistance.5. According to the combining ability analysis, the resistance investigation of stem borer and rice quality analysis results,14 combinations have been selected preliminary.